The present invention relates to an intake and exhaust device of a multi-cylinder engine provided to, for example, an automobile.
Conventionally, an intake and exhaust device has been developed for an engine of, for example, an automobile for the purpose of increasing an engine output.
For example, JP2009-097335A discloses a device including a turbocharger. The device is provided with a plurality of independent exhaust passages that are respectively connected with exhaust ports of cylinders and independent from each other, a manifold section provided upstream of the turbocharger and where the independent passages assemble, and valves that are provided to the manifold section and can change flow areas of the independent passages. The device reduces the flow areas of the independent passages by the valves so that exhaust gas in the cylinder on exhaust stroke flows from a predetermined independent passage to the manifold section at comparatively high speed. Further, the exhaust gas in the other independent passages is sucked downstream thereof by a so called ejector effect caused by a negative pressure produced around the exhaust gas flowing at high speed that affects the other independent passages in the manifold section. In this manner, an amount of gas supplied to the turbocharger is increased to increase the engine output.
While the output of the engine itself is desired to be increased as above, in regard to mass producing, for example, vehicles, it is desired to suppress a performance variation between vehicles due to a manufacturing variation, etc.
The present invention is made in view of the above situations, and provides an intake and exhaust device of a multi-cylinder engine that can suppress a performance variation due to a manufacturing variation, etc.